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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/xtensa/platforms/xtfpga/lcd.c
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/*

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 * Driver for the LCD display on the Tensilica XTFPGA board family.

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 * http://www.mytechcorp.com/cfdata/productFile/File1/MOC-16216B-B-A0A04.pdf

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 *

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 * This file is subject to the terms and conditions of the GNU General Public

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 * License.  See the file "COPYING" in the main directory of this archive

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 * for more details.

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 *

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 * Copyright (C) 2001, 2006 Tensilica Inc.

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 * Copyright (C) 2015 Cadence Design Systems Inc.

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 */

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#include <linux/delay.h>

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#include <linux/init.h>

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#include <linux/io.h>

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#include <platform/hardware.h>

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#include <platform/lcd.h>

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/* LCD instruction and data addresses. */

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#define LCD_INSTR_ADDR		((char *)IOADDR(CONFIG_XTFPGA_LCD_BASE_ADDR))

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#define LCD_DATA_ADDR		(LCD_INSTR_ADDR + 4)

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#define LCD_CLEAR		0x1

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#define LCD_DISPLAY_ON		0xc

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/* 8bit and 2 lines display */

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#define LCD_DISPLAY_MODE8BIT	0x38

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#define LCD_DISPLAY_MODE4BIT	0x28

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#define LCD_DISPLAY_POS		0x80

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#define LCD_SHIFT_LEFT		0x18

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#define LCD_SHIFT_RIGHT		0x1c

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static void lcd_put_byte(u8 *addr, u8 data)

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{

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#ifdef CONFIG_XTFPGA_LCD_8BIT_ACCESS

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	WRITE_ONCE(*addr, data);

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#else

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	WRITE_ONCE(*addr, data & 0xf0);

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	WRITE_ONCE(*addr, (data << 4) & 0xf0);

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#endif

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}

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static int __init lcd_init(void)

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{

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	WRITE_ONCE(*LCD_INSTR_ADDR, LCD_DISPLAY_MODE8BIT);

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	mdelay(5);

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	WRITE_ONCE(*LCD_INSTR_ADDR, LCD_DISPLAY_MODE8BIT);

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	udelay(200);

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	WRITE_ONCE(*LCD_INSTR_ADDR, LCD_DISPLAY_MODE8BIT);

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	udelay(50);

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#ifndef CONFIG_XTFPGA_LCD_8BIT_ACCESS

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	WRITE_ONCE(*LCD_INSTR_ADDR, LCD_DISPLAY_MODE4BIT);

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	udelay(50);

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	lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_MODE4BIT);

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	udelay(50);

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#endif

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	lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_ON);

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	udelay(50);

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	lcd_put_byte(LCD_INSTR_ADDR, LCD_CLEAR);

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	mdelay(10);

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	lcd_disp_at_pos("XTENSA LINUX", 0);

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	return 0;

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}

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void lcd_disp_at_pos(char *str, unsigned char pos)

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{

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	lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_POS | pos);

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	udelay(100);

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	while (*str != 0) {

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		lcd_put_byte(LCD_DATA_ADDR, *str);

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		udelay(200);

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		str++;

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	}

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}

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void lcd_shiftleft(void)

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{

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	lcd_put_byte(LCD_INSTR_ADDR, LCD_SHIFT_LEFT);

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	udelay(50);

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}

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void lcd_shiftright(void)

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{

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	lcd_put_byte(LCD_INSTR_ADDR, LCD_SHIFT_RIGHT);

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	udelay(50);

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}

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arch_initcall(lcd_init);

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